* Check for intersection between placed blocks and entities.
+ Implemented GetPlacementCollisionBox, to permit custom placement collision boxes for blocks.
* Factored block-entity placement checking into another function in cPlayer.
- Removed vector min/max functions
* Use GetWorld to get the world in DoesPlacingBlocksIntersectEntity.
+ Added block height checks, allow different cEntity subclasses to decide whether they will prevent block placement.
